Hollow punch



yma

mlm

CII

Patented Dec. 1, 1925.V

UNITED SITES PATENT OFFICE.

JOI-IN JENSEN, OF ROCKFORD, ILLINOIS, ASSIGNOR TO TI-IIINEY-METAL TOOL COM- PANY, OF ROCKFORD, ILLINOIS, A. CORPORATION OF ILLINOIS.

HOLLOW PUNCH.

Application filed September 4, 1,923.

To all 'ui/0m t may] concern:

Be it known that I, JOHN JENSEN, a citizen ot' the United States, residing at Rock tord, in the county of itfinnebago and State oit Illinois, have invented a certain new and useful Hollow Punch, of which the following' is a specilication.

The invention pertains to tools of the type commonly known as hollow punches, and the object of the invention is to provide a punch oi this type having al centering pin and at the same time constructed with a detachable cutting' bit or tool so that a set of' such tools ot varying sizes may be used interchangeably in a common shank or holder.

I have illustrated in the accompanying` drawings a preferred form of my invention.

Figure 1 is an elevation section of a tool constructed in accordance with the invention.

Fig. 2 is a side elevational view showing' the several parts in detached relation and arranged in the order in which they are assembled.

Fig. 3 is a horizontal sectional view on a somewhat enlarged scale, taken in the plane of line 3 3 o't Fig. 1.

Fig. 4 is a fragmentary vertical sectional view showing' a larger cutting tool in position in the shank or holder.

Figs. 5 and 6 are lower end views of Figs 1 and 4 respectively. i

The punch comprises a shank 7 having at its upper end a head 8 to receive the blows o-t a hammer. The. lower end of the shank is constructed so as to lform a holder for the cutting tools or hits to be used interchangeably, one of said bits being indicated in Fig. 1 by the numeral 9 and another one oit said hits being indicated in Fig. 4 by the numeral 9.

In thus constructing: the lower end of' the shank to form the holder for the bits .0*0 I provide an axial socket 10 in the lower end portion of the shank, and the latter, it will he observed, is somewhat enlarged. as shown at Ta (Fis. l).

Said socket 10 is adapted to receive the upper end portion of the cutting tool or bit which for this purpose has its upper end shaped to form a stem 11 adapted to lit snue'- lv in the socket with its upper end abutting' the inner end wall of the socket. At the lower end ot the stem 11 the bit is enlarged radially outwardly, to a dial'letr StlbStan- Serial No. 660,702.

tially equal to that of the lower end of the shank, to provide a shoulder 12 adapted to engage with the extreme lower end of the shank and thus coact with the upper end ot the stein in receiving` the force of the blow.

rlhe cutting' tool or bit is bored out, axially thereof at its lower end, as shown at 13 (Fig. and 13l (ltig. 4) and the extreme lower end of the bit is then shaped to form an annular cutting edge 14 or 14.

In order detachably to secure the cutting' tool or bit in its holder, I preferably provide a set screw 15 entered through a threaded aperture in one wall of the socket 10 and adapted to engage with a recess 16 in the peripheral wall of the stem 11.

To provide the punch with a centering vpiu I bore the lower end ot the shank 7 ally thereof as at 17 to a diameter adapted to receive the upper end of a pin indicated at 18. Likewise I bore the tool or bit axially thereof asindica-ted at 19 so that the pin may pass through the cuttingtool and into the shank, the lower end portion of the pin being;` concentric with the annular cutting` edge 14. The pin may be securedin the shank in any suitable way, but preferably I em ploy a key-pin 20 entered through a trans verse hole 21 near the lower end of the shank (Fig. 3), this pin being offset slightly from the axis of the shank so as to lie within a cut-away portion or notch 22 in the side of the pin near its upper end. The notch 22 provides shoulders 23 and 23 which are adapted to engage with the key-pin 20 to limit the longitudinal sliding movements of the centering pin 18. Normally the pin 18 is held in its lowermost position with the upper shoulder 23 against the stop pin 20. bv means of a coiled expansion spring 24 entered in the upper end of the bore 17. The lower end of the centering; pin is sharpened to a point as at 25.

It will be observed that the centering pin is carried by the shank in such a way as to yield under pressure applied to the lower end. At the same time the cutting tools or bits are capable of being quickly and easily interchanged. Moreover, it will be observed that while the cutting tools or bits are thus made separately from the shank or holder, the combined abutting; surfaces provided by the shoulder 12 and the upper end of the stem 11 are substantially equal to the cross sectional area of the shank at its lower' end, so that the force of the blow is transmitted to the cutting' tool just as effectively as though the two were made an integral part of the shank.

lower end, the lower end ofthe shank hav-v ing a socket formed therein and the cutting tool having at its upper end a portion of reduced diameter forming a stein adapted snugly to lit in said socket, there being opposed annular shoulders on the shank and the tool, a screw for fastening the parts rigidly together with said annular shoulders abutting, a centering pin, said shank and 4cutting tool having -alined axial bores adapted to receive said pin, a spring entered in the upper end of the bore in theshank tending to force the pin downwardly, and means carried by said shank to retain said pin in the shank and to limit the downward vmovement thereof.

2. A hollow punch comprising a main body portion providing a shank, the upper end oil which is arranged to receive the inn` pact of a hammer, the lower end of the shank having' a socket formed therein thereby providing an annular shoulder at the bottom of the shank, said-shank having also an axial bore extending upwardly from the base of said socket, a centering pin extending into said boie, a pin carried by said shank engaging a notch inv said centering pin to retain thev pin in the shank and to limit its outward movement, a spring in said bore above said pin tending to keep the pin in its outward position, a cutting tool having at its upper end a portion of reduced diaineter forming a stein adapted to lit snugly in said Socket, said tool having-an axial bore to permit passage oi' said centering pin therethrough and an annular Shoulder adapted to` i'it against the shoulder on the shank, and a set screw entered in said shank through the wall of the socket adapted to engage the stein of said -tool to fastenvtheshank and tool rigidly together with said annular shoulders abutting.

In testimony whereof, I have hereunto atf# fixed my signature.

JOHN JENSEN. 

